Project Summary Innovation in surgical technology has led to less invasive approaches that translate into shorter hospital stays, making procedures more broadly available. The diffusion of new procedures in people with Alzheimer's Disease and related dementias (ADRD) may be beneficial if they can be performed safely. However, increasing use could also expose patients with ADRD to additional risk, resulting in deteriorating cognition thereby hastening the need for long term care. Deciding which type of procedure to pursue, or whether to forego surgery altogether, requires balancing potential benefits with the harms and the subsequent deterioration of cognition. With their emphasis on evidence-based medicine, improved physician-to-physician communication through information technology and culture of shared decision-making, accountable care organizations (ACOs) suggest a philosophical shift that many believe will foster value-based healthcare, which is critical for people with ADRD. Collectively, these changes may encourage ACOs to be more selective of the surgical technologies they adopt and in whom they implement them. The goals of this supplement are to develop a better understanding of the use of major surgery in patients with ADRD and to anticipate the broader impact of health reform on this population. The aims are: 1) To assess the use of new surgical technologies and short-term outcomes in patients with ADRD, and 2) To measure the effect of ACOs on rates of major surgery and short-term outcomes in patients with ADRD. This proposal has real world implications for payers and policymakers as they struggle with designing effective policies to improve outcomes for the growing population with ADRD. Importantly, the results will also inform patients with ADRD and their caregivers as they struggle with making decisions about whether or not to proceed with major surgery.